OCT4 but not SOX2 expression correlates with worse prognosis in surgical patients with triple-negative breast cancer

Abstract

Background

Octamer-binding transcription factor 4 (OCT4) and SRY (sex determining region Y)-box 2 (SOX2) are common biomarkers of cancer stem cells, which contribute to the pathological processes of several carcinomas, while little is known about the effects of OCT4 and SOX2 on the prognosis of triple-negative breast cancer (TNBC). The purpose was to evaluate the correlation of tumor tissue OCT4 and SOX2 expressions with clinicopathological features and overall survival (OS) in surgical TNBC patients.

Methods

127 surgical patients with TNBC were enrolled in this cohort study. Tumor tissue samples were obtained during the operation. OCT4 and SOX2 expressions were assessed by immunofluorescent staining.

Results

32 (25%) TNBC patients with OCT4 positive expression (OCT4⁺), 21 (17%) patients with SOX2 positive expression (SOX2⁺), and 11 (9%) patients with both OCT4⁺ and SOX2⁺ were observed. OCT4 expression was positively associated with histologic grade (P < 0.001), pathological tumor size (P = 0.014), N stage (P < 0.001) and TNM stage (P < 0.001), while SOX2 expression was positively correlated with histologic grade (P < 0.001), pathological tumor size (P = 0.033) and Ki-67 expression (P = 0.016). Kaplan–Meier (K–M) curves suggested OCT4⁺ was correlated with shorter OS compared with OCT4⁻ (P < 0.001), while no correlation between SOX2⁺ with OS in all patients (P = 0.128) was observed. Multivariate Cox model indicated that OCT4⁺ (P < 0.001) were independent factors for worse OS.

Conclusions

Tumor tissue OCT4 but not SOX2 expression was positively correlated with histologic grade, pathological tumor size, N stage and TNM stage, and it could be served as an independent biomarker to predict worse prognosis in surgical patients with TNBC.

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